1. Field of the Invention
The invention relates to a rotary compressor housing for use in a movable-vane compressor that is utilizable as a supercharger for an internal combustion engine.
2. Description of the Prior Art
It is unavoidable that the compressor housing is heated and caused to thermally expand by adiabatic compression of air while the compressor runs. In general, the center housing is axially secured to the opposite side housings or the like by four or more bolts which are circularly equidistantly disposed to pass through the center and the side housings and fasten them as one body. The bolts prevent the bolted portions of the center housing from radially thermally expanding but permit the radial thermal expansion of the four intermediate portions between the adjacent bolted portions, so that the inner periphery of the center housing thermally expands in the form of a somewhat square. Therefore, there is the possiblity of a trouble that the inner periphery of the center housing is thermally deformed to reduce the performance of compressor.
In Japanese Published Unexamined Patent Application No. 58-65988 published on Apr. 19, 1983, we have shown a rotary compressor provided with a rotary sleeve interposed between a center housing and a rotor and floatingly supported by compressible fluid. The compressor is particularly suitable for a supercharger with use for an automobile engine required to operate over a wide range of speeds. The rotary sleeve rotates together with the vanes to prevent frictional heat and wear at the apex of each vane. However, if the inner periphery of the center housing is thermally deformed the bearing capacity of the air-bearing room defined between the inner periphery of the center housing and the outer periphery of the rotary sleeve may lower to the extent that the rotary sleeve scuffs the inner periphery of the center housing.